This is a Ph.D. training proposal. The primary aim is to train Ph.D. candidates in areas of biomedical and biological sciences relating to environmental toxicity, especially in areas relating to cellular signal transduction in mammalian cells, in areas that relate to activities in the labs of participating UCSD faculty members and in areas relating to the endeavors of several San Diego Corporate Partners in environmental sciences, screening and remediation. The Aims of the training program are: a) to train graduate students in areas of signal transduction and modern cellular and molecular biology and associated techniques relating to environmental toxicity and its remediation, with a combination of laboratory and course work. b) to expose graduate students to research and daily activity in a environmental company or governmental regulatory agency. c) to provide a course in career alternatives, drawing on the San Diego industrial environmental community and on representatives of the EPA, such that students are scientifically prepared for careers in the environmental industry, in government, in private consulting, or in academia. d) to provide courses on regulatory and ethical issues that may be encountered by scientists working in the environmental industry. The training program combines core course work, lab rotations, grant/proposal writing, advanced courses and dissertation research. The core courses in the first year focus on cellular and molecular aspects of mammalian systems, including cell biology, molecular biology,, cellular and molecular pharmacology, systems physiology and statistical analysis. During the first year, students will also complete four 10 week lab rotations: two rotations with Program members, one rotation in the labs of a Corporate Partner and an additional laboratory experience in the San Diego Super Computer Center Working on the development and use of the Program's Geographic Information System (GIS) database on hazardous substances, water quality and public health of the San Diego- Tijuana (Mexico) border region.